The present invention relates to a device that displays the level of a video signal in order to monitor the video signal.
For example, Patent Document 1, shown below, discloses a conventional device that displays the level of a video signal in order to monitor the video signal. FIG. 1 shows a display method employed in the device disclosed in Patent Document 1 and known as a diamond display. As shown in FIG. 1, an upper part of the diamond display indicates a first vector (G+B, −G+B) corresponding to G (green) and B (blue) components of an RGB component signal. A lower part of the diamond display indicates a second vector (−G−R, −G+R) corresponding to the G (green) component and an R (red) component of the RGB component signal. When the first and second vectors are displayed outside a first area 11 and a second area 12 bounded by dotted lines, an observer can recognize that the level of the RGB component exceeds a predetermined value or is in a gammut error state.
[Patent Document 1] Japanese Patent Laid-Open No. 6-261345
The observer must read the state of the RGB (how the level of each of the R, G, and B components approaches or exceeds a predetermined value) from the diamond display (first and second vectors).
Further, for example, if the RGB component signal contains a natural image, the observer must pay attention to both upper and lower parts (the first area 11 and second area 12, bounded by dotted lines) of the diamond display when observing which color in the natural image is in the gammut error state. In addition, the diamond display corresponding to a natural image appears blurred, like clouds.